Oh yeah, your question immediately made me think of "black swan events", the economic parable about things we've never seen or even imagined, until one day some

Oh yeah, your question immediately made me think of "black swan events", the economic parable about things we've never seen or even imagined, until one day someone sees/imagines it. So loosely speaking Einstein's General Theory of Relativity was an improbable idea in this black swan sense.